Objective      To determine the effect of Liver X receptor β (LXRβ) on the cell proliferation and fiber formation of radial glial cells in hippocampal dentate gyrus (DG) of perinatal mice.       Methods      Embryonic 18.5 d (E18.5) and postnatal(P2) mice hippocampus was collected

and then immunohistochemic

al assay was used to detect the expression of the markers for cell proliferation (proliferating cell nuclear antigen

PCNA)

for radial glial cells (brain lipid binding protein

BLBP) and Nestin. The results of LXRβ knockout mice and WT controls were compared.       Results      LXRβ was strongly expressed in the hippocampus both at E18.5 and P2 of WT mice

of which densely stained positive cells mainly localized in the DG. At E18.5

LXRβ knockout mice showed the decreased number in the PCNA positive neurons (

P

<

0.01) and BLBP-labeled radial glial fibers (

P

<

0.05) when compared with WT mice

but

no change of the number of radial glial cell bodies was found (

P

>0.05). At P2

compared to E18.5

the number of PCNA positive neurons in the DG was slightly increased

which was decreased by LXRβ knockout (

P

<

0.05). Moreover

the morphology of BLBP labeled radial glia cells in the DG at P2 was different from that in the DG at E18.5

of which the number of cell bodies was slightly increased

but radial glial fibers disrupted. LXRβ knockout induced significant decrease in the number of radial glial fibers (

P

<

0.05)

although did not affect the number of radial glial cell bodies in the DG (

P

>0.05). As another marker for radial glial cells

Nestin was expressed in the similar pattern to that of BLBP

but the nestin labeled radial glial fibers were disrupted in the LXRβ knockout mice both at E18.5d and P2.       Conclusion      LXRβ plays important role in the cell proliferation and formation of the fibers of radial glial cells in the DG of perinatal hippocampus.